Dr Heinz and Mr Perry
by Spiritofdawolf
Summary: When Doof discovers how to make his ancestor's Jekyl and Hyde formula, he plans to convert it to energy and blast himself so he can take over the Tri-State Area. But things go wrong when Perry gets hit instead by accident. At first Doof is having fun with the mishap, but later discovers that if he doesn't reverse the effects soon, Perry might be stuck in 'Mr. Hyde' form for good.
1. Chapter 1

Dr. Heinz and Mr. Perry

By: Spiritofdawolf

Summary: When Doof discovers how to make his ancestor's Jekyl and Hyde formula, he plans to convert it to energy and blast himself so he can take over the Tri-State Area. But things go wrong when Perry gets hit instead by accident. At first Doof is having fun with the mistake, but eventually discovers that if he doesn't reverse the effects on his little frienemy soon, Perry might be stuck in 'Mr. Hyde' form for good.

-Just in time for Halloween. ;) Well, a little early, but still. Hope you enjoy. I also hope you have some good spooky fun for Halloween.

0000

Chapter one- Old Family Recipe

It was another typical day in Danville. Phineas and Ferb were up to their usual 'shananigans' as Candace normally put it. Their pet platypus was lounging by the tree in the backyard watching the antics of his owners.

It was a crisp autumn day. Halloween wasn't too far away. Just a couple of days.

As the platypus half listened in on his boy's plans; a small part of the discussion being about what they were going to dress up this year; his wrist started beeping.

The platypus directed his attention to his watch and recognized the all too familiar signal that his boss wanted to see him. He sighed as he got up and checked to be sure no one was looking before going to one of his secret entrances.

As he headed inside to go down, he heard the classic

"Hey, Where's Perry?" of his owners and rolled his eyes knowingly.

Within seconds he had plopped down into his chair and turned the monitor on.

His boss, Major Monogram, appeared on the screen.

"Good morning Agent P." he addressed the monotreme who gave him his full attention.

"Dr. Doofenshmirtz has been digging through his family archives for the past day or so. We don't know what he's looking for, but no doubt, he's probably searching for something evil he can use for a scheme. So, go on out there and make sure he's not doing anything evil."

Perry saluted the Major before heading out.

As the Major watched his agent take off, he heard the voice of his intern next to him, off screen.

"Sir, did you see my costume for Halloween yet?"

"Yes, I did." Monogram rolled his eyes. "Several times."

Meanwhile, Perry arrived at the building of his nemesis as the casual evil jingle played.

He landed on the floor just in time to be snagged by a mechanical arm and thrown in a large carved pumpkin. It was a silly trap, Perry had to admit, but at least it went with the time of year.

"Ah, Perry the Platypus, good to see you." Doofenshmirtz said stepping into view.

"Do you like your trap?" he asked with a smirk looking at Perry looking through the jack-o-lantern's eyes at him.

"I figured since it was almost Halloween, I oughta come up with a Halloween themed trap. Ooh, Ooh. And he's the fun part." He said as he snapped his fingers and a small light came on inside the pumpkin by Perry giving it the traditional glow of a Jack-o-lantern in the dark; save for the platypus inside it.

"Viola, a Perry-lantern!" he chuckled at his own joke.

Perry rolled his eyes, but couldn't help but smirk slightly himself.

"Now, Perry the Platypus, I suppose you're wondering what I've got planned for today. Well, you remember last Halloween when I told you the story about my ancestor Jekyl Doofenshmirtz making a formula to turn himself into a monster?" he began.

Perry nodded with an eyebrow raised, wondering where Doof was going with this. Somehow he had a suspicion.

"Yeah, well, being that it's Halloween I've been looking for just the right scheme. Then I remembered my ancestor and started to look through my family's archives and locate his files. You'll never guess what I found!" Doof said starting to get excited.

Perry frowned slightly, having an idea what it probably was.

"That's right, Perry the Platypus," he squeaked with delight. "The notes for how to make his infamous formula! However, I didn't want to drink it, you know, in case it tasted bad. So, I decided to convert the formula into energy that I intend to blast myself with so I can take over the Tri-State Area!" he cackled.

Perry's frown narrowed into a glare. He definitely had to stop this. If he failed the outcome would be catastrophic.

"Behold, Perry the Platypus!" he said pushing a button revealing his hidden Inator.

"The Jekyl and Hyde formula converted into an energy beam Inator!"

Perry gave him a look that said, 'seriously?'

"What? I couldn't think of a better name!" Doof retorted causing another eye roll from Perry.

"Roll your eyes all you want, Perry the Platypus, that's not going to stop me from finally becoming the ruler of the entire Tri-State Area!" he shouted.

As Doof headed over to start up the Inator, Perry crawled out of the pumpkin. Yes, catchy trap, but very poorly planned.

Doof had just reached the Inator when Perry body slammed him.

"Prepare to see the most-OOF!" Doof cried out as he fell to the floor from Perry's strike.

"Perry the Platypus, how'd you get.." he started then stopped. "Oh, come to think of it…I probably should have sealed the top of the pumpkin…yeah…"

He was cut off by the Monotreme delivering another punch to his face..

"Okay, Perry the Platypus, now you're getting on my nerves." Doof frowned, kicking the platypus off of him and running back to the Inator. He switched it on.

Thinking quickly, Perry hurled the jack-o-lantern trap at the Inator in an intent to hit the switch back off. However, instead of turning it off, it just broke the lever.

Perry face palmed as Doof turned to him. "Really? Really, Perry the Platypus?" he said flatly.

"You do realize that nothing is stopping it from fir-" he started, then stopped and smirked.

"Ha! You did it to yourself this time, Perry the Platypus!" he taunted as he ran back to the front of the Inator. It would go over any second. He wanted to make sure he was in the right position to get zapped in time.

Perry glared. Despite the mishap, he could still destroy the Inator if he could get to it in time before it fired. He made a running leap and kicked at the Inator. To buy time, he could at least kick the gun away from Doof before it fired whilst he searched for the self destruct button.

He succeeded in knocking the gun away from Doof who responded with a "Oh, come on!" and scrambled to get in front of it again. Perry knocked him down as Doof tried to run to it.

Perry continued to look for the self destruct button. Doof sulked for a second but then noticed that the pumpkin wasn't completely smashed. Grabbing what was left of the pumpkin, he threw it at Perry.

"Take that, Perry the Platypus!"

Perry didn't see it in time and got knocked back off of the Inator and tumbled to the floor. He rubbed his head slightly. The Inator was getting louder and whirring as it was only a second away from shooting.

Perry looked to see that he'd been knocked into the path of the beam. His eyes widened as he tried to get up and move out of the way in time.

"Perry the Platypus, look out!" Doof cried out, not having expected this outcome. He was surprised that he was actually concerned for a second. But didn't have much time to reflect on it as the next second, a beam fired and engulfed the agent before he could move.

Doof was wide eyed as he looked to his nemesis.

"Perry the Platypus?"

The steam from the beam cleared revealing the small agent on the floor looking dazed for a second. But other than that, nothing seemed to have changed.

Doof's concern quickly turned to disappointment.

"Aw, man. It doesn't work!" he groaned. "I was really hoping it would work." He sulked again.

Perry shook his head and looked himself over. Thankfully nothing appeared to have changed. Perry breathed a sigh of relief. Then got back up. He still had a job to do, even if the Inator didn't work.

Leaping on the Inator again, he found the self destruct button and quickly pressed it.

"No! What are you doing?!" Doof cried, even though he had a good idea.

The Inator rumbled and finally blew up. Another scheme averted.

"Oh, come on!" Doof complained. "It doesn't even work and you destroy it anyway?"

Doof activated his jet pack and took off.

"Curse you, Perry the Platypus!" the Dr. yelled his signature line as the monotreme flew off.

Perry grinned slightly at that. Same old, same old. All the same it was lucky for him that the Inator was a failure.

"Good work, Agent P!" the Major congratulated him when he returned. "Another job well done!"

Perry saluted and Monogram clicked off the screen. As Perry went to head back up to his family.

As he did so, he couldn't help but think what could've happened if it had worked. He wasn't sure what he would have done if it had.

Well, regardless, he'd destroyed the Inator. Now it couldn't happen. Then again, what if Doof tries to rebuild it?

He resumed the position of a mindless pet as he walked over to his family, who weren't aware of his secret; the thoughts still swimming in his mind.

Well, for the time being at least, there was nothing to worry about.

….or was there?

-R&R. I'll try to update soon.


	2. Feeling Strange

Chapter 2- Feeling Strange

Perry spent the remainder of the evening with his family, as he always did. The nagging thoughts in his head calmed down and were soon forgotten as he cuddled up by his boys and relaxed.

A little later, after dinner, Perry was getting ready to take a nap. It would be bedtime for his boys very soon as well. As Perry headed to the boys room, a brief wave of sharp pain occurred in his head and he stifled a yelp of pain.

It was almost as if suddenly a freak headache had struck him. It passed quickly and he was fine again. That was odd. What could've brought that on?

Perry shrugged it off and continued to head to the boys room and plopped down on Phineas' bed to nap, waiting on his boys. It would still be a couple hours before they went to bed, but Perry relaxed anyway. Soon he was curled up snoring softly.

Back with Doofenshmirtz, he was still fretting over his Inator.

"I don't understand what could've gone wrong." Doof said to seemingly no one as he studied the remains of the Inator. "It should have worked."

He sighed and went to his chair and sat down. His eyes narrowed slightly in thought as he looked over at his ancestor's notes.

"Maybe I need to double check. Maybe I forgot something."

He scanned over the notes for a moment before realizing he kept rereading the same line several times and still it wasn't registering.

"Geez, I must be tired. I can't make sense of it. You know what? I'm just going to bed. I'll figure it out tomorrow." He concluded to himself as he got up and headed to his room to conk out.

Phineas and Ferb finally entered their room to find the sleeping platypus curled up on Phineas' bed.

"Aw, isn't that sweet, Ferb?" Phineas said. "He was waiting for us." Ferb nodded.

They noticed Perry start to kick his little feet out and chatter slightly.

"He must be dreaming." Ferb pointed out, with a small smirk.

"I bet it's a fun dream." Phineas added as he and Ferb got ready to settle in for the night.

Little did they know, their little buddy's dream wasn't so fun.

_Perry saw himself in his dream. But…it didn't look like him. His fur was a darker shade of green and his bill and webbed feet were a darker orange. His whole color contrast was somehow darker._

_Perry, or what apparently was Perry in the dream was standing in the middle of absolute chaos. Everyone was panicking and running around aimlessly. The sky seemed kinda dark. Doofenshmirtz must've taken over somehow._

_Perry had to stop him and save the Tri-State Area. There was no time to lose!_

_But…wait..why wouldn't he move? And…and why was he smiling like that?_

_The supposed Perry walked through the chaos until he met up with Doof whom was sitting on the stoop of the Mayor's office looking out at the calamity. There was something floating through the sky, but it was hard to make out from the angle he was looking. His focus was more on the scrambling citizens, feeling strangely amused by their reactions._

"_Ah, Perry the Platypus." Doof said grinning slightly as he looked at him. "Isn't that a lovely sight? Chaos as far as the eye can see."_

_The supposed Perry nodded, that smirk still on his face. _

"_I didn't expect things to go so well. I wasn't even aware you had it in you." Doof admitted._

"_But I did it." He smirked looking back at the platypus._

"_And I couldn't have done it without you, new partner." Doof's voice rang out in his head._

Perry jolted awake suddenly feeling nauseous. He looked over to his boys whom luckily he hadn't disturbed out of their sleep. The room was dark. It was the middle of the night.

As carefully as he could so as not to awaken the boys, he climbed down from Phineas' bed and began to waddle towards the bathroom.

He checked to be sure that the coast was clear before standing up on his back feet and heading over to the bathroom mirror.

He looked himself over. He looked flushed. Like he was getting sick or something.

Perry groaned quietly as he checked his eyes and throat. He put a hand to his forehead and realized he felt warm. Almost like he had a fever. Something wasn't right here.

He couldn't get sick! He had planned to go back to Doof's tomorrow and make sure he wasn't trying to fix whatever had gone wrong with the Inator.

Perry stepped down from looking in the mirror and was overcome by the wave of sharp pain in his head again. He winced and bit the end of his bill trying not to cry out in pain and wake the family.

Getting up, he felt a little dazed as he made his way out of the bathroom. Maybe it would be a safe bet to go to his lair for now to rest. Maybe it'll ease up. If not he concluded that Phineas and Ferb would have to take him to get checked out.

He stumbled over to one of his lair entrances and went inside to head down.

The ride down proved to be a mistake as he felt even more nauseous once he arrived. His vision blurred and he whimpered slightly.

What was wrong with him? What could be causing this? And what was the deal with that nightmare? Why did Doof call him his 'partner'?

Perry found it hard to think straight as he held his head.

And why had he looked so different in the dream? Another pinch of pain hit him as he yelped in pain. He was shaking now as he collapsed on the ground, feeling weak.

His vision was fading as he started to pass out from the pain.

Why…?

000

Beep beep beep!

The sound of his watch woke him up. Perry looked around a little perplexed. Had he fallen asleep in his lair? Why would he do that?

He sat up and rubbed his head. What exactly happened last night? Why was he in his lair?

He snapped out of it when he realized the watch was still beeping and looked back at it then at the lair. As strange as it was, he couldn't help but find it rather convenient that he was already where he was supposed to be. He sighed and stood up trying to fix himself up, (why did he look like a mess?), as he headed to his chair to click on the monitor.

He sat down and pulled out his hat and put it on. Then clicked the monitor on.

"Agent P! It's about time! We've been—great googly moogly, Agent P, are you feeling okay?" Monogram exclaimed to the agent who shrugged. At the moment, he felt fine. Other than the strange fact that he'd happened to wake up in his lair.

"You look a mess. Did you get sick or something?"

Perry shrugged again trying to straighten himself up. To be honest, he didn't exactly remember.

"You sure you're good for going after Doofenshmirtz today?" Monogram seemed concerned.

Perry nodded. Maybe the fresh air would clear his head.

"Well, okay…" Monogram said hesitantly. "Doofenshmirtz looks to be in the process of rebuilding the Inator you destroyed yesterday. Seems a little odd. But you best go take a look see."

Perry saluted and jumped in his hover car and left the lair. He soon arrived at his Nemesis' lair to see him tinkering with the different pieces of his Inator from yesterday.

"Oh! Oh, Perry the Platypus!" he exclaimed realizing he hadn't had time to make a trap because he was preoccupied with the Inator.

Perry looked around with an eyebrow raised. Doof rubbed the back of his neck awkwardly.

"Yeah, I uh…I didn't get around to making a trap for you just yet."

There was an awkward pause. Perry continued to glare at his nemesis.

"I…um…I'm also not done with the Inator." He said gesturing to the scattered pieces that still needed to be assembled.

"To tell you the truth, I'm still trying to figure out what went wrong." Doof admitted. "All morning I've been rereading my ancestor's notes and as far as I can tell, it should've worked. There's got to be something I'm missing."

Perry looked at his nemesis and realized he wasn't kidding. He sighed and uncrossed his arms and his gaze softened ever so slightly. But in reality, he was relieved to hear that.

Doof gazed back at him and sighed. "I'm sorry, Perry the Platypus, but until I can figure this out I think we're gonna have to take a rain check for today. I'll be sure to let you know when I figure it out so you can come thwart me. It would feel too weird to start without you."

Perry smirked slightly. That was one thing that made Doof different from the other villains. His willingness to give his nemesis a chance to beat him. It was one of the things that made their relationship work so well.

"I'm hoping I can figure it out by Halloween night though." Doof spoke up. "I'd love to terrorize the neighborhood."

Perry rolled his eyes. 'I'm sure you would.' He thought.

"So….do we have a deal? I promise not to start my scheme until you get here." Doof pressed, trying to convince the agent to give him the chance.

Perry sighed and nodded. He could tell Doof was telling the truth.

'But when I get here, your butt's getting kicked.' He thought.

Perry tipped his hat to him and started to turn and walk away.

"Thanks, Perry the Platypus." He heard his nemesis say.

He was about to deploy his jet pack and take off when he heard his nemesis speak again.

"Oh, Perry the Platypus?"

Perry turned to face him.

"Are you feeling all right, by the way? You look a little…I don't know…flushed. Like you're getting sick or something." Doof pointed out.

Perry nodded wearily. However, he couldn't help but wonder what he looked like. This was the second time today that someone had said that he didn't look good.

"Well, okay…" Doof said reluctantly. "Cause I can't bring myself to fight you if you're sick. I'd get some rest, just to be on the safe side." He advised.

Perry nodded again and deployed the jet pack and headed off. Doof watched him go wondering what could be going on with his nemesis. Hopefully he wasn't getting sick or something.

As Perry headed home, he thought about what Doof said about him not looking good. Monogram had said something like that earlier. This worried Perry a little. He'd have to be sure to double check himself when he got home.

Then a thought hit him. Phineas and Ferb. They were probably wondering where he was. They didn't see him this morning. He didn't want to worry them. But if he let them see him in this state, whatever it must look like, they might be more worried.

As he landed, he saw them in the backyard trying to figure out what to do. They seemed concerned about Perry not being there. The last time he was gone during the morning, they had feared something might be wrong.

Maybe they were right this time. But Perry wanted to be sure. He felt fine, but somehow everyone else was thinking otherwise. Time to get to the bottom of it.

As discreetly as he could, he sneaked into the house and headed to the bathroom, hoping no one was using it at the time. As he headed for the bathroom he saw Candace coming down the hall and hid himself. He watched as she continued on to go see what was going on with Phineas and Ferb.

He heard a flush and saw Lawrence exit the bathroom before heading to the kitchen. Not long after Perry heard Linda's voice talking to Lawrence. He sighed, the coast was clear for the moment. He quickly scuttled into the bathroom and looked himself over in the mirror.

What he saw startled him. His whole complexion seemed thrown off. His color seemed a little drained. His normally mint green fur seemed a somewhat paler shade of green. It was subtle, but it still startled him.

He double checked his face. Even that seemed a little off. His eyes held a sense of exhaustion in them and his face was slightly flushed. No wonder they thought he was sick.

But….why didn't he feel sick? Something weird was going on here. Now, he began to wonder more than ever what happened last night.

Getting down form the bathroom mirror, he scurried elsewhere in the house so as not to be seen. He ended up crawling under Phineas' bed, trying to think things over. The boys didn't check under their beds all that often, so he figured it was a safe zone for now, whilst he tried to figure this out.

Once under the bed, he went back to thinking.

Okay… this morning he woke up in his lair. But why? Perry thought harder and remembered earlier last night he was originally in the boys' room like he was now. Why did he leave?

As if to answer his question that brief moment of sharp pain hit him again. This jolted Perry to his senses.

That's right…he'd left because of the headache. He'd gone to check himself in the bathroom mirror as he just had moments ago. Then it seemed to get worse, so he crawled off to the sanctity of his lair to avoid waking up the boys and worrying them.

That's when he must've passed out, he remembered.

Maybe it's best to have his boys take him to the doctor to be sure he was okay.

Wait a minute…Doctor…There was something else that had rattled him last night. Something besides the freak migraine.

Something involving a nightmare…but what was it? Perry raked his brain, but continued to have trouble recalling it. Whatever it was, was probably connected to the migraine.

But, what was causing them? He thought back to even further yesterday when he was battling Doof. Doof had said something about discovering his ancestor's special formula or something and that somehow played a part in his scheme.

A brief smirk came across his face remembering the lame jack-o-lantern "trap" that Doof had used on him. Doof had gone to activate his Inator and Perry had stopped him using the so called trap.

Wait, hold on. There had also been a blinding light and Doof calling his name. Did something go wrong? He recalled Doof complaining afterwards that it hadn't worked and that Perry had destroyed the Inator anyways.

Perry was still trying to turn all this over in his head. Trying to make sense of it. Come to think of it, he recalled feeling a blast of energy hit him. But whatever it was supposed to do supposedly hadn't worked.

Perry frowned. Whatever this was, it was probably being caused by Doof's Inator hitting him. Looks like he was going to have to make another trip to see his nemesis. Crawling out from under the bed he headed back to one of his secret entrances again and headed down to the lair.

Once he arrived he realized he felt queasy again. Usually the ride down to the lair didn't upset his stomach. Hopefully this wasn't going to be a continuing occurrence.

As he tried to settle his stomach he focused on how he would go about confronting Doof on the matter. Doof probably wasn't aware of this. At least that's the way it seemed. Still, that didn't stop Perry from feeling a little irritated at him.

He was broken out of his thoughts, as he realized the nausea just seemed to be getting worse. Perry sat down as he started to get the shakes. Getting nervous, he took deep breaths to try and calm things.

'Doof, if I make it through this, I'm going to kill you.' He thought as he did so.

Perry doubled over and finally laid down, still shaking. Why wouldn't it stop? He squeezed his eyes shut as he winced. A groan escaped him. He opened his eyes to notice his sight was getting blurry. A wave of dizziness came over him as he tried to make sense of what he was seeing.

He could've sworn his complexion was changing again. Getting darker. Was it for real or was he seeing things in his dazed stupor? He couldn't tell.

He closed his eyes again as the shakes got worse. A faint voice echoed in his head. It sounded almost like Doof. But when would he have heard him say what was said just now?

"_I didn't expect this to go so well. I didn't even know you had it in you…"_ it started.

"_But I couldn't have done it without you…"_ The last couple words seemed faint. But it sounded something like 'partner'.

Perry put his hands to his head and held it as the shakes turned into near convulsions. His body writhed as he rolled back and forth letting out various pained and fearful chatters.

Then it all stopped suddenly. The pain, the nausea, the shakes. His vision cleared again and he shook his head as he got up. What was that all about?

Granted, he was glad that it was over, it was still strange. He looked around the lair again.

Why was he here again? Oh, yeah…that's right! He was going to head out to see Doof.

'I wonder what he's up to.' Perry thought as he grabbed his jet pack again to head off.

Perry thought about it for a second before shrugging it off.

'Regardless, it'll be nice to see him again.' He smiled slightly before finally taking off to head to Doof's.

However, he failed to realize that his fur was now a darker shade of green and his bill and feet were a darker orange…

-R&R. Hmm…I wonder how Doof's going to react.


End file.
